Coronary artery chronic total occlusion (CTO) is a heart disease that causes a decrease in the blood flow of concerned patients. A coronary obstruction is considered a CTO if: 1) it causes a complete blockage of a coronary artery, 2) the duration is more than 3 months, and 3) it has a clinically significant decrease in blood flow. Percutaneous coronary intervention (PCI) is one of the most effective procedures to treat this disease.
During the surgery procedure, surgeons need to track the progress of the catheter in the arteries and insert the guidewire around the blockage of the target vessel in order to further operate (e.g., stent placement) via real-time fluoroscopy imaging (e.g., X-Ray). However, tracking is challenging because the vessels are not visible in the fluoroscopy images without injecting dye (i.e., a contrast agent) into the target vessel. Dye is harmful to the patient and injection needs to be minimized. In a clinical case, usually surgeons inject minimal dye dose to one artery and watch the vessel tree and locate the target vessel. The dye dose keeps the vessel visible for a couple of seconds. This process is called Cine stage and the resulting images with dye injection are referred to as angiography images.
A Cine video is recorded and used for guiding CTO PCI. However, due to the breathing and cardiac motion, the target vessel is moving. Therefore, surgeons have to estimate vessel location in the fluoroscopy images utilizing recorded Cine images and guess during the process of CTO wire insertion. Due to coronary vessel tree's complexity (e.g., potentially including many branches), experienced surgeons may even need to attempt many times to reach the target vessel. This process may take hours and dye needs to be injected many times to help surgeon keep track of the relationship between CTO wire and target vessel. Additionally, it should be noted that the fluoroscopy imaging used during the procedure is also harmful to the patient. Thus, it is desired to provide vessel tracking techniques which minimize the time required during surgical operations.